Oil or other liquid fuel pump



R. OLDHAM OIL OH OTHER LIQUID FUEL PUMP July 9, 1935.

Filed July 19, 1933 2 Sheets-Sheet 1 F IG.1.

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R. OLDHAM OIL OR OTHER LIQUID FUEL PUMP July 9, 1935.

2 Sheets-Sheet 2 Filed July 19, 1933 FIC.7.

,1 m u m. 5 m n w y/ /m .T// ,//////m/1 Patented July 9, 1935 lin Great Bri am c, i932 8 maints. (GCH. lim-41) 'I'his invention relates to oil or other liquid fuel pumps of the constant stroke reciprocating plunger type in which a relief port in a blind-ended reciprocatlng plunger is adapted to release the pressure in the pressure chamber by overrunning the end of or co-operating with a port in the contacting sealing Wall of the pump barrel bore.

In single relief control pumps, the constant release of pressure eventually scores and wears the relief edge which in turn affects the volumetric eiliciency, and the chief object is to overcome this difficulty. l

According to the invention, the plunger and adjacent contacting wall of the pump barrel cooperate to afford a double seal to the release of pressure throughout the forcing stroke.

In an embodiment of the invention, the relief port is so arranged in the plunger that it is double sealed, or sealed at both ends, against the release of delivery pressure throughout the forcing stroke by means of the Wall of the pump barrel bore. Thus the relief port is arranged in the side of the plunger and release of the pressure is effected at any predetermined point by co-operation of the upper end of the plunger relief port with the end of the wall of the pump barrel bore and the simultaneous co-operation of the lower end ment or setting of the plunger and barrel the lower end of the relief conduit in the plunger may lead into a diagonally cut or inclined recess in the plunger which is adapted to co-operate with a relief port or alternatively the suction port in 5 the barrel simultaneously with the co-operation of the upper end of the conduit with the inclined end face of said barrel.

According to a further feature of the present invention therelief port in the plunger has two 10 controlling edges adapted to co-operate simultaneously with relief ports or the equivalent on or in the pump barrel so as to release the pressure or break the double seal at any point in the forcing stroke.

A suction or admission port in the pump barrel may in some cases also constitute one of the relief ports with which one of the plunger port controlling edges co-operates.

According to a still further feature of the present invention, the double seal to the release of pressure is broken by the controlling or relief edge of the plunger port (so-operating simultaneously with upper and lower relief ports in the pump barrel.

In order that the invention may be clearly understood and readily'carried into effect, the same of the'plunger relief port with a relief or .suction Will DOW be mOI'e fully described With reference port in the pump barrel.

Thus a relief conduit is provided, having a portion of its length formed by surfaces of the plunger and another portion of its length formed by` cooperating surfaces of the pump barrel or cylinder. This conduit is sealed at two points by the cylinder wall overlying the upper and lower ends of that portion of the-conduit which is formed by the surfaces in the plunger. This condition exists throughout the forcing stroke of the plunger, and communication from the dischargeV side to the suction side is completely cut off at these two points. The surfaces of the plunger forming the conduit, and the surfaces of the cylinder adapted to cooperate therewith to form another portion of the conduit are so arranged that they cooperate to break both seals simultaneously or in other wordsto uncover or open the upper and lower ends of the conduit in the plunger simultaneously.

If desired the delivery' may be varied by co-operation of the upper end of the relief conduit in the plunger in known manner with an inclined end face of the pump barrel, the two being relatively rotatable, and in this connection and in order to ensure the simultaneous breaking of both seals irrespectiveof the relative angular adjustto the examples illustrated in the accompanying drawings, in whichz- 30 Figure 1 is a sectional elevation of a pump constructed according to one embodiment of the invention.

Figure 2 is an enlarged view of part of the plunger and barrel shown in Figure 1. A 35 Figure 3 is a similar view to Figure 2 but shows a. modification of the plunger relief port.

Figure 4 is a part sectional elevation showing a pinion and sleeve or saddle for rotatably adjusting one of the plungers of a multiple pump. 40

Figures 5, 6, '7 and 8 are similar fragmentary sectional elevations of the upper end of the pump plunger and barrel, and each illustrates a different embodiment or modication of the invention.

Referring to the embodiment of the invention 4 illustrated in Figure 1, the pump comprises a casing l having inlet ports in communication with supply ports and pipe line 4 in the pump casing l, and a bored pump barrel 5 wherein 50 the reciprocating plunger 6 works. The lower end of the pump barrel 5 projects through the borenf the casing I, and an annular space constituting a suction chamber 8 is afforded between the pump barrel 5 and casing I. The upper end 55 of the pump barrel 5 is formed with an inclined end 9 and with a suction port I0. A relief port or conduit II is formed in the side wall of the upper end of the reciprocating plunger 6, and said port II communicates at its lower end with a diagonally cut or inclined recess I2 in the plunger which recess I2 is adapted to co-operate with a port I3 in the barrel 5. A pressure chamber is afforded above the inclined face 9 of the pump barrel 5 by a screwed union nut or sealing plug I4 fitting in the top of the pump casing I, and seating on a circumferential edge or shoulder I5 on the upper end of the pump barrel so as to retain the latter in position. Thus the plunger and cylinder 5 have surfaces formed or shaped to provide a relief conduit leading from the discharge or pressure chamber to the suction chamber, the several portions of the conduit being designated respectively II, I2, i3. The pressure chamber is provided with a delivery port closed by a spring loaded sealing plug I6 and a pipe line is fitted or attached to the union nut I4 with its opposite `end connected say to an injector associated with an internal combustion engine. 'I'he foot of the plunger is engaged by a bored tappet I8 working Within the casing I and a spring I8 bears against a locating collar upon the tappet I8 and encircles the pump barrel 5, which is secured against rotation by a set screw 22, whilst the plunger 6 is rotated from a rack 2lx and p'inion 2I through the medium of a depending sleeve or saddle 2D having a slot connection with pins or projections 23 on the plunger 5, the arrangement being such as to permit of rotation of the plunger without interfering with its reciprocation. The plunger is reciprocated against the action of the spring I9 by a cam (not shown) acting on the bored tappet member I8 which is retained when in its lowest position by a. ring 24.

The inclination of the upper or controlling edge of the inclined recess I2 in the pump plunger 6 is such that, irrespective of the relative angular setting of the plunger 6 and barrel 5, it will uncover the port I3 at the same time as the upper end of the port II overruns or is uncovered by the inclined face 9 on the upper end of the barrel 5. Thus the pressure of the forcing stroke will be instantaneously released and flow back into the suction chamber through the relief port orv passage I I, recess I2 in the plunger 5 and port I3. According to the rotation of the plunger 6 the point at which the relief port II registers with the inclined face on the upper end of the pump barrel 5 and at which the recess I 2 simultaneously co-operates with the port I3 can be varied so that the whole or part of the liquid duringthe forcing stroke can be displaced back into the suction chamber 8 by way of the relief port II, recess I2 and port I3. When the pressure is released on the forcing stroke, the spring loaded pressure sealing plug I6 is forced by its spring loading to return to its normal position, thereby closing and sealing the delivery ports in the pressure chamber and also performing the duty of releasing the pipe line pressure to normal, which gives an instantaneous cut oi at the injector and prevents dribbling of the liquid from the nozzle of the injector.

It will be seen'that for the setting illustrated (Figures l and 2) the plunger is disposed so that the whole of the liquid will be displaced back into the suction chamber 8 by Way of port I3. If, however, the plunger be partially rotated the release will take place at a point above the lower end of the inclined face of the pump barrel 5 thus providing the minimum delivery, whilst if the plunger be rotated approximately to degrees, release will take place when the plunger is at the extreme end of its stroke, thus providing the maximum delivery.

The operation of the modified form shown at Figure 3 is the same as in the construction shown in Figures 1 and 2.

In this modification, the relief port I I is in the form of a coarse pitch screw threaded groove around the periphery of the plunger, and the pitch is such that, when the plunger is in any of its Various positions of angular adjustment, a portion of the groove may register with the bottom of a slot 9X in the upper end of the barrel 5 at the same time as the inclined edge of recess I2 co-operates with port I3.

As shown in Figure 4 the arrangement of the sleeve or saddle 20 may be such that it is rotatable relative to the pinion 2I for adjustment of each individual pump unit when used in multiple form so that individual settings of the deliveries can be made to the respective cylinders, independent of the meshing teeth between pinion 2I and rack 2IX; also, in the event of any wear taking place in the pinion teeth, a new portion can be presented to the rack for engagement. For this purpose the sleeve or saddle 20v is cut through the upper portion of its side walls, and fitted with a tapered screw 28 whereby the side walls of the saddle 20 can be expanded, thus securing and locking the loose ring pinion 2| in position.

As illustrated in all of the Figures 1 to 4 of the drawings, the suction III is shown as passing through the body of the pump barrel obliquely; in some cases however, this passage may be formed less obliquely or even at right angles to the axis of the pump bore.

Referring to Figure 5 of the drawings, the plunger 6 has a relief portI II in the form of two diametrically opposed angular recesses having oppositely inclined upper controlling or relief edges IIx, said angular recesses being placed in direct communication at their lower corners as shown so as to constitute a single plunger port. One of the controlling or relief edges IIx cooperates with the bottom of a relief port I3 through the wall of the pump barrel 5, which port I3 also serves as a suction or admission port when the plunger 6 is at the bottom of its stroke, whilst the other controlling or relief edges I I X co-operate simultaneously with the lower end of a diametrically opposed slot relief port 9X cut in the wall of the barrel 5 from its upper end. The two controlling or relief edges I Ix each extend equally round the plunger 6 and their inclination is such that irrespective of the relative angular setting or adjustment of the plunger and barrel to vary the delivery, the simultaneous release action will take place. The position of the parts shown in Figure 5 is such that all the oil would be displaced through the port I3 and no pumping would take place.

In the construction shown in Figure 6 the relief port I I with its two controlling or relief edges IIx is located at a greater distance from the blind end of the plunger 6, and the relief ports I3 and 9X are at a corresponding lower level, whilst a separate suction or admission port I0 is formed through the barrel 5. The relief port 9X in this example is in the form of an angular bore or passage extending through the wall of the barrel from the upper end thereof, and the relief port I3 constitutes a return to the suction side. The simultaneous release of pressure by the controlling or relief edges IIx irrespective of the relative angular setting or adjustment of the plunger and barrel is the same as in the arrangement shown in Figure 5.

Referring now to Figure '7 of the drawings, the plunger relief port II; is in the form of two inclined recesses located at different levels and each having a controlling edge IIx, said inclined recesses being in direct communication by way of a duct IIy cut in the' plunger 6. The upper inclined recess extends only half-way `round the plunger 6 and the lower inclined recess extends fully around it, whilst the controlling or relief edge llx of the upper recess co-opeiates with a through relief port 9x which leads to the discharge or pressure chamber of the pump. The controlling or relief edge IIIX of the lower inclined recess simultaneously co-operates with a through relief port I3 in the barrel 5 at a lower level. A suction or admission port Il) is formed through the barrel 5 at a position diametrically opposed to the port 9X and said port lll is uncovered by the blind end of the plunger li when the latter is at the bottom of its stroke. By relative angular adjustment of the plunger .6 and barrel 5 through approximately 180 the delivery is continuously variable. The parts are shown in the drawing as in the no-pumping position. The lower inclined recess in the plunger need only extend half way round the plunger and on the opposite side thereof to the upper inclined recess.

Referring to Figure 8 of the drawings, in which the plunger 6 is shown at the bottom of its stroke, the pump barrel 5 is formed with an upper relief port 9X which communicates at its upper end directly with the pressure chamber (not shown), and a relief port I3 at a lower level and which constitutes a. return to the suction side, whilst I is an admission or suction port which, as shown, is uncovered by the plunger 6 when the latter is at the bottomof its stroke.

The plunger relief port I2 is in the form of a peripheral recess having an upper controlling or relief edge I2x the inclination of which is such that said edge will co-operate with the upper and lower relief ports 9X, I3 respectively simultaneously to break the double seal afforded by the wall of the pump barrel throughout the forcing stroke.

'I'he delivery may be varied by relative rotation of the plunger and barrel within the limits of the controlling or relief edge I2x which is such as to simultaneously co-operate with the relief ports 9X, I3 irrespectiveof the relative angular adjustment or setting of the plunger and barrel within said limits.

Instead of the upper relief .port 9x being in the form of an angular bore as shown, it may be in the form of a longitudinal slot cut through the pump barrel and extending from its upper end, or it may be in the form of a longitudinal recess or groove cut in the inner face of the Ipump barrel from its upper end.

It will be understood that the embodiments illustrated are by Way of example only, and that the constructional details can be variously modied without departing from the na-ture of the invention. For instance, the inclined controlling edge afforded at the end of the pump barrel bore may be provided or formed by cutting a V-shaped, or other slot recess or notch having at least one inclined side, in the otherwise right angular end of the pump barrel.

I claim:

1. A pump comprising a cylinder, a recipro- .defined by controlling edges n the cylinder wall,

the cylinder wall and periphery of the plunger adjacent said edges serving to provide a double cut-olf seal for said conduit at opposite ends of the portion thereof lying in said plunger during the forcing stroke of said plunger and being such as to break `said double cut-off seal at a predetermined point and establish communication from the discharge chamber to the relief chamber to terminate the effective forcing stroke of the plunger.

2. A pump in accordance with claim l characterized in that the conduit is so arrangedin the plunger that its lower end therein cooperates with the portion of the conduit in the cylinder wall leading to the relief chamber simultaneously with the uncovering of the upper end of the conduit in communication with the discharge chamber.

3. A pump comprising a cylinder, a reciprocable plunger mounted therein, and relief and discharge chambers, said cylinder and plunger being arranged for relative angular adjustment, and said cylinder and plunger having surfaces formed to provide a relief conduit from said discharge chamber to said relief chamber, thesaid -surfaces of the plunger forming a portion of the relief conduit being in the form of inclined recesses cut in the wall of the plunger and disposed in communication with each other,'the angular adjustment of said plunger and cylinder serving to determine the effective stroke of said plunger by the opening of said conduit and the establishment of communication between said chambers at respectively different points in said stroke at different angular adjustments, said surfaces forming said conduit being such as to provide two cut-01T seals in the conduit during the effective pumping stroke of the plunger and, at the termination of the effective portion of said stroke, to open and break said two seals simultaneously, irrespective of the angular adjustment of saidplunger and cylinder, said two cut-off seals being formed by the cylinder walls blinding the opposite ends of the portion of the conduit in the plunger.

4. A pump comprising a cylinder, a reciprocable plunger mounted therein, and relief and discharge chambers, said cylinder and plunger being arranged for relative angular adjustment, and said cylinder and plunger having surfaces formed to provide a relief conduit from said,discharge chamber to said relief chamber, said surfaces of the plunger forming a portion of the conduit being in the form of two intercommunicating inclined recesses diametrically opposed in the.

same transverse plane and having their inclined controlling edges disposed to cooperate simultaneously with diametrically opposed relief ports disposed at the same level in the pump barrel, said ports constituting portions of said relief conduit leading respectively to the discharge chamber and the relief chamber, the angular adjustment of said plunger and cylinder serving to determine the eective stroke of said plunger by the opening of said conduit and the establishment of communication between said chambers at respectively different points in said stroke at different angular adjustments, said surfaces forming said conduit being such as to provide two cut-off seals in the conduit during the effective pumping stroke of the plunger and, at the termination of the effective portion of said stroke, to open and break said two seals simultaneously, irrespective of the angular adjustment of said plunger and cylinder, said two cut-off seals being formed by the cylinder walls blinding the opposite ends of the portion of the conduit in the plunger.

5. A pump comprising a cylinder, a reciprocable plunger mounted therein, and relief and discharge chambers, said cylinder and plunger being arranged for relative angular adjustment, and said cylinder and plunger having surfaces formed to provide av relief conduit from said discharge chamber to said relief chamber, the said surfaces of the plunger forming a portion of the relief conduit terminating at opposite ends in two inclined recesses disposed at different transverse planes and having their inclined controlli/ng edges disposed to cooperate simultaneously with relief ports disposed at correspondingly spaced transverse planes in the barrel, 'said ports constituting portions of said relief conduit leading respectively to the discharge chamber and the relief chamber, the angular adjustment of said plunger and cylinder serving to determine the effective stroke of said plunger by the opening of said conduit and the establishment of communication between said chambers at respectively different points in said stroke at different angular adjustments, said surfaces forming said conduit being such as to provide two cut-off seals in the conduit during the effective pumping stroke of the plunger and, at the termination of the effective portion of said stroke, to open and break said two seals simultaneously, irrespective of the angular adjustment of said plunger and cylinder, said two cut-off seals being formed by the cylinder Walls blinding the opposite ends of the portion of the conduit in the plunger.

6. A pump comprising a cylinder, a reciprocable: plunger mounted therein, and relief and discharge chambers, said cylinder and plunger being arranged for relative angular adjustment, and said cylinder and plunger having surfaces formed ,to provide a relief conduit from said discharge chamber to said relief chamber, the said surfaces of the plunger forming a portion of the relief conduit being in the form of a peripheral recess having an upper inclined controlling edge disposed for simultaneous cooperation with upper and lower relief ports extending through the cylinder wall, the said ports constituting a portion of the relief conduit and leading respectively to said discharge chamber and said relief chamber, the angular adjustment of said plunger and cylinder serving to determine the effective stroke of said plunger by the opening of said conduits and the establishment of communication between said chambers at respectively differentl points in said stroke at different angular adjustments, said surfaces forming said conduit being such as to provide two cut-off seals in the conduit during the effective pumping stroke of the plunger and, at the termination of the effective portion of said stroke, to open and break said two seals simultaneously, irrespective of the angular adjustment of said plunger and cylinder, said two cut-off seals being formed by the cylinder walls blinding the opposite ends of the portion of the conduit in the plunger.

7. A pump comprising a cylinder, a reciprocable plunger mounted-therein, and walls defining relief and discharge chambers, said cylinder and plunger having surfaces formed to provide a relief conduit communicating from said discharge chamber to said relief chamber after said plunger has reached a predetermined point in. its forcing stroke, said surfaces of the plunger` being such that the portion of the conduit in the plunger terminates at opposite ends in open portions on the periphery of the plunger which are closed by the cylinder walls so as to form two cut-off seals in said conduit during at least a portion of the effective stroke of said plunger, the open portions being such as to open said conduit and break said two seals after the plunger has reached a predetermined point in its effective forcing stroke.

8. A pump comprising a cylinder, a reciprocable plunger slidably mounted therein, and relief and discharge chambers, said cylinder and plunger having surfaces formed to provide a relief conduit leading from said discharge chamber to said relief chamber, the portion of the conduit in the plunger terminating at points spaced from the ends of the plunger in openings disposed on the periphery thereof, the portion of the conduit in the cylinder comprising openings communicating respectively with the discharge and relief chambers and adapted to register simultaneously with the respective openings in the plunger conduit when the plunger has reached a predetermined point in its forcing stroke, the simultaneous closing of the openings on the periphery of the plunger by the cylinder walls serving to provide two cut-off seals disposed at substantially opposite ends of the portion of the conduit formed in the plunger.

RICHARD OLDHAM. 

